JP3072171B2 - Air flow guide silencer on fan suction side - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air flow guide silencer on a fan suction side.

[0002]

2. Description of the Related Art Conventionally, an airflow is guided from a predetermined axis (generally, the center axis of a fan suction port) to the axis in a direction orthogonal to or oblique to the axis, and thereafter, the airflow is guided. In the case of a suction mode in which the air is turned into a direction parallel to the axis and is sucked into the fan suction port, generally, as shown in FIG.
The outlet opening 2a on the side connected to the suction port 8 is formed on one side surface, and the airflow A is introduced in a direction orthogonal (or oblique) to the center axis P of the outlet opening 2a.
There is provided a chamber 2 'in which "b" is formed on the periphery.

In order to mitigate the noise generated on the suction side of the fan due to the suction in the above-mentioned suction mode, as shown in FIG. The outlet 2a of the chamber 2 'and the fan inlet 8
And a silencer X connecting between the chamber 2 ′ and the fan 7.

That is, an air flow A is introduced into the chamber 2 'from the introduction opening 2b of the chamber 2' in a direction orthogonal (or oblique) to the center axis P of the outlet opening 2a. In the direction parallel to the center axis P of the outlet opening 2a, and during the suction process from the outlet opening 2a of the chamber 2 'to the fan inlet 8, the sound absorbing material in the silencer X described above. The sound absorbing function of 24 is used to mute the sound.

[0005]

However, in the above-mentioned conventional structure, in addition to the installation of the chamber 2 ', a silencer X is interposed between the outlet 2a of the chamber 2' and the fan suction port 8. However, the entire installation space is increased in the direction of the center axis P of the outlet opening 2a, and there is a problem that the installation property is poor.

Further, even if the silencer X is interposed between the outlet opening 2a of the chamber 2 'and the fan suction port 8 at the cost of increasing the installation space, the noise generated on the suction side of the fan 7 is generated. There was also a problem that the noise was still large and the silencing effect was low.

In view of this situation, an object of the present invention is to reduce the required installation space by a rational structure,
This is to make it possible to effectively reduce noise generated on the fan suction side.

[0008]

Means for Solving the Problems [Characteristic configuration of the invention according to claim 1] In the invention according to claim 1, the conical inner trunk and the annular outer trunk are provided at the inner central portion of the outer trunk. Arranged in a state where the top of the inner trunk is located, an annular internal air passage is formed between the two trunks using a sound absorbing material as a wind path wall constituting material. An annular opening formed between both bodies on the top side is an outlet opening concentrically communicating with the fan inlet, and the other end side opening of the internal air passage is provided at the center axis of the outlet opening. An annular opening formed between the two bodies on the bottom side of the inner body in an orthogonal or oblique direction is an introduction opening for introducing an airflow from a peripheral part of the body, and a surface of the outer body on the side of the internal air passage. A reversal point of a tangent inclination direction with respect to the center axis center in an intermediate portion between the introduction opening and the outlet opening. And a convex curved surface having a cross-sectional shape in which a dimension in a direction along the center axis center and a dimension in a direction perpendicular to the center axis center are each equal to or larger than a difference between inner and outer radii in an annular shape of the outlet opening. In addition, the surface of the inner body on the side of the inner air passage is a concave curved surface in which a tangent inclination angle with respect to the center axis becomes smaller toward the outlet opening from the inlet opening. The direction of the air path gradually changes toward the direction parallel to the center axis, and the width of the air path gradually decreases as going from the inlet opening to the outlet opening.

According to a second aspect of the present invention, in the implementation of the first aspect, the end of the internal air passage on the side of the outlet opening is provided with the outlet opening. A straight air path portion extending in parallel with the central axis with an air path width equal to the difference between the inner and outer radii in the annular shape is formed.

[0010]

[Operation of the invention according to claim 1] That is, in the conventional structure shown in FIG.
The air flow A is caused by the suction opening of the fan 7
At the same time, the airflow A is introduced in a state of being deviated in the direction of the center axis P of the outlet opening 2a (the vertical direction in the figure), and the airflow A also flows in the chamber 2 'in a deviated state,
In addition, the direction of the airflow A suddenly changes at the outlet opening 2a,
Furthermore, vortices are generated in the chamber 2 ′ due to these drifts and sudden changes in the direction of the air flow, and a sudden shrinkage of the air flow path at the time of the outflow from the outlet opening 2 a.
The silencer X interposed between the outlet opening 2a of the chamber 2 'and the fan suction port 8 causes noise that cannot be sufficiently silenced, and also causes a large pressure loss.

On the other hand, in the invention according to the first aspect (see FIGS. 1 and 2), the internal air passage 21 (ie, one end formed between the two trunks 20A and 20B at the top side of the inner trunk 20A). Are formed at the bottom side of the inner body 20A in a direction perpendicular (or oblique) to the center axis P of the outlet opening 22. The air flow from the introduction opening 23 in the peripheral part of the body is centered on the outlet opening 22 during the passage of the air passage by the air passage formed by the annular opening at the other end formed between the trunks 20A and 20B as the introduction opening 23). It is deflected in a direction parallel to the axis P and guided to the outlet opening 22.

The surface Sx of the outer shell 20B on the side of the internal air passage is formed into a convex curved surface, and the surface Sx of the inner shell 20A on the side of the internal air passage is formed.
When y is a concave curved surface, the direction of the air passage gradually changes to a direction parallel to the center axis P as the inner air passage 21 goes from the introduction opening 23 to the outlet opening 22, and By providing a wind path in which the width of the wind path becomes gradually smaller, the above-mentioned air flow is smoothly changed, and the inlet opening 23 and the outlet opening 2 are formed.
2 (the fan suction port 8) is smoothly increased in the flow velocity in accordance with the opening area ratio.

In order to surely and effectively achieve these smoothing, the concave curved surface Sy on the side of the inner body 20A is formed such that the tangent inclination angle with respect to the central axis P is increased toward the outlet opening 22 from the inlet opening 23. Is reduced, the convex curved surface Sx on the outer shell 20B side is provided at an intermediate portion between the introduction opening 23 and the extraction opening 22 with a reversal point u in a tangential inclination direction with respect to the center axis P. And the central axis P
And a dimension (GD) / 2 in a direction perpendicular to the center axis P are a lead-out opening 2
By making the cross-sectional shape larger than the inner-outer radius difference W (that is, the opening width of the lead-out opening 22) in the annular shape of No. 2, the internal air path 21 has a sufficiently large bending radius with respect to the opening width W of the introduction opening 22. Air flow with air flow As
Of the convex curved surface Sx on the introduction opening 23 side with respect to the reversal point u under the condition that the air flow As can be diverted without difficulty while changing the air flow As easily (in short, Due to the presence of a surface portion that once brings the introduced airflow As in the direction of the center axis P in the direction opposite to the outlet opening 22), the suction action of the fan 7 causes the introduction opening 23 to move in the direction of the center axis P (vertical direction in the drawing). ) So that it covers evenly.

That is to say, the introduction airflow As from the introduction opening 23 is led out to the outlet 22 in a state where the drift or the sudden change in the direction of the airflow or the generation of the vortex is effectively avoided.
Can be very smoothly changed to a direction parallel to the central axis P of the air inlet P, and the increase in the flow velocity of the introduced air flow As in accordance with the opening area ratio between the inlet opening 23 and the outlet opening 22 can also be smooth. Then, under such a condition that the air flow deflection and the increase of the flow velocity are effectively smoothed, the sound absorption member 24 constituting the air path wall of the internal air path 21 receives the suction noise of the fan 7 and the noise in the internal air path. The noise generated on the suction side of the fan can be effectively reduced by absorbing the airflow noise at the fan. In addition, the pressure loss can be effectively reduced by effectively smoothing the air flow deflection and the increase in the flow velocity as described above.

[Operation of the Invention According to Claim 2] According to the invention according to claim 2 (see FIGS. 1 and 2),
The linear air passage portion 21a provided at the end of the internal air passage 21 on the side of the outlet opening 22 (that is, the air passage width is equal to the inner-outer radius difference W in the annular shape of the outlet opening 22 and is parallel to the center axis P). The airflow flowing out of the outlet opening 22 is rectified by the rectifying action of the extending air passage portion) so that the center axis P
And a better rectification state along.

[0016]

According to the first aspect of the present invention, the annular opening in the peripheral portion of the container body is orthogonal or oblique to the center axis of the outlet opening. In adopting a suction mode in which an airflow is introduced and the introduced airflow is sucked into the fan suction port from the outlet opening, the airflow is interposed between the outlet opening and the fan suction port as compared with the above-described conventional structure shown in FIG. The silencer is unnecessary (or smaller) and the required installation space is effectively reduced, while the noise generated on the fan suction side can be effectively reduced and the pressure loss is also reduced. And the required power of the fan can be reduced.

In addition, since the drift at the inlet opening can be prevented, in the usage mode in which the heater or the cooler is provided at the inlet opening in the peripheral part of the container, the heat exchange efficiency at the heater or the cooler due to the drift can also be prevented.

[Advantage of the Invention According to Claim 2] According to the invention according to claim 2, the outflow airflow from the outlet opening can be made to be in a better rectified state along the center axis of the outlet opening. This makes it possible to further smoothly reduce the noise generated on the suction side of the fan by making the air flow of the fan more smooth, and to reduce the required power of the fan more effectively.

[0019]

Next, an embodiment will be described.

FIGS. 1 and 2 show an air conditioner, in which a box 2 provided with intakes 1 for taking in ambient air Ar at both lateral ends is installed on a floor 3, and each intake 1 is sequentially arranged from the outside. A filter 4 and a cooler (or heater) 5 are provided.

Reference numeral 7 designates an opening at one end as an inlet 8, and
This is an axial fan provided with a straight cylindrical fan casing 10 having the other end side opening as the discharge port 9. The fan 7 is configured such that the end of the fan casing 10 on the suction port 8 side is directly opposed to the upper wall of the box body 2. The suction port 8 is communicated with the inside of the box body 2 in a state where the suction port 8 is electrically connected.

That is, by the operation of the axial flow fan 7, the ambient air Ar is taken into the box 2 from the intake port 1. In this taking-in process, the ambient air Ar is taken out by the filter 4 to remove dust and a cooler (or a heater). 5
The temperature of the ambient air Ar taken in is controlled by the above, and the air As taken into the box 2 after dust removal and temperature control is sent out from the discharge port 9 of the fan 7 to the air supply duct 11.

In the above axial fan 7, reference numeral 12 denotes a motor, and reference numeral 13 denotes a rotor which is directly connected to the rotating shaft of the motor 12 and has a large number of blades 14 provided on the periphery.

Reference numeral 15 denotes a discharge-side silencer interposed between the fan discharge port 9 and the air supply duct 11, which has an outer shell 15A connecting the fan casing 10 and the air supply duct 11, and An inner body 15B is provided at the center of the vessel so as to be concentric with the center axis P of the fan 7 while being supported by the support legs 16, and between the outer body 15A and the inner body 15B. An annular internal air passage 17 that connects the fan discharge port 9 and the air supply duct 11 is formed, and a sound absorbing material 18 such as glass wool is filled in each of the outer shell 15A and the inner shell 15B.

That is, from the fan discharge port 9 to the air supply duct 1
The fan discharge noise leaking to the first side is absorbed by a sound absorbing material 18 as a component of the air passage wall of the internal air passage 17 in the discharge side silencer 15 so as to suppress the noise.

The inner wind path side surface of the outer shell 15A and the outer surface of the inner shell 15B are each formed of a suitable material such as a perforated plate, glass cloth, or film so as to protect the filled sound absorbing material 18 from airflow. It is covered with a coating material 19, and a higher noise reduction effect is obtained by the resonance effect of the coating material 19 than the noise reduction effect obtained only by the sound absorbing material 18.

On the other hand, the inside of the box 2 is provided with a suction-side silencer 20 which also serves as a guide for the air flow As to be sucked into the fan suction port 8, and its structure is shown in FIGS. As shown in the figure, a conical inner body 20A having a flattened apex at a height from the bottom wall to the upper wall of the box body 2 is arranged concentrically with the center axis P of the fan 7 as a body component. In the same manner, the inner diameter is substantially equal to the diameter D of the fan suction port 8 and the outer diameter is substantially equal to the bottom diameter G of the conical inner body 20A. The outer shell 20B is arranged on the upper wall side of the box 2 so as to be concentric with the center axis P of the fan 7 and is housed in the box 2.

That is, the conical inner body 20A and the annular outer body 20B are arranged in the box 2 with the top of the inner body 20A positioned at the center of the inner side of the outer body 20B. 20
A, 20B, an annular internal air passage 21 is formed around the center axis P of the fan, and an opening on one end side of the internal air passage 21 is provided between the two shells 20A, 20B on the top side of the inner shell 20A. The formed annular opening 22 is opened in the upper wall of the box body 2 as a lead-out opening 22 that communicates concentrically with the fan suction port 8, and the other end of the internal air passage 21 is connected to the fan center axis. Core P (in other words, the center axis of outlet opening 22)
An annular opening 23 formed between the two trunks 20A and 20B on the bottom side of the inner trunk 20A in a direction perpendicular to the main body 20A is opened in the box 2 as an introduction opening for introducing the air current As from the peripheral part of the container. It has a body configuration.

The internal air passage 21 has a sectional shape including the center axis P of the fan 7, and the direction of the air path is orthogonal to the fan center axis P from the introduction opening 23 to the outlet opening 22. The shape is gradually changed from the direction to the direction parallel to the fan center axis P and the width of the air passage is gradually reduced. In the process of guiding the introduced airflow As from the introduction opening 23 of the section to the fan suction port 8, the airflow As is smoothly changed from the introduction direction perpendicular to the fan center axis P to a direction parallel to the center axis P, and The flow velocity is increased by an amount corresponding to the opening area ratio between the introduction opening 23 and the exit opening 22 in a form of gradually compressing the introduction airflow As with the deflection.

The conical inner cylinder 20A and the annular outer cylinder 2
Each of OBs is filled with a sound absorbing material 24 such as glass wool, and as described above, smoothes the airflow state in the process of leading to the fan suction port 8 to prevent the turbulence of the airflow causing noise. In addition to the above, the fan suction noise leaking from the fan suction port 8 to the internal air passage 21 and the airflow noise generated in the internal air passage 21 are absorbed by the sound absorbing material 24 as a member of the air passage wall of the internal air passage 21. It is like that.

The inner surface of the conical inner body 20A and the outer surface of the annular outer body 20B are provided with a suitable covering material 25 such as a perforated plate, glass cloth, or film, similarly to the discharge side silencer 15. To protect the filled sound absorbing material 24 from airflow while improving the noise reduction effect due to the resonance effect of the coating material 25.

While the inner diameter of the annular outer body 20B is made substantially equal to the diameter D of the fan suction port 8, the conical inner body 20A
When determining the diameter Ws of the top portion in the following equation, W = {(D−Wh) / 2} · K1 where Wh: an appropriate value near 1.0 is selected for the diameter coefficient K1 of the rotor 13. Then, the opening width W of the outlet opening 22 (that is, the difference between the inner and outer radii in the annular shape of the outlet opening 22) is determined, and the diameter Ws of the top of the conical inner body 20A is determined from the opening width W of the outlet opening 22 (one example). Ws = about 0.8 Wh to 1.0 Wh).

The outlet opening 2 in the internal air passage 21
At the end on the second side, a straight air passage portion 21a extending downward from the outlet opening 22 by a predetermined dimension Ha in parallel with the fan center axis P with an air passage width equal to the opening width W of the outlet opening 22 is formed. It is.

The predetermined dimension Ha is determined by the size of the lead-out opening 2.
It is selected from an appropriate dimensional range using the opening width W of 2 as a reference value.

That is, the outlet 2 in the internal air passage 21
By forming the above-mentioned straight air path portion 21a at the end on the two sides, the air suction of the axial fan 7 is made smoother.

Regarding the cross-sectional shape including the fan center axis P, the surface Sx of the outer shell 20B on the side of the internal air passage 21 (that is, the surface Sx)
The inner surface of the internal air passage 21 on the convex side (the inner surface of the air passage) has a dimension in the direction along the fan center axis P (in this example, Ha + Ra) and a dimension in the direction perpendicular to the fan center axis P ((G− D)
/ 2) have a cross-sectional shape equal to or greater than the air passage width W of the outlet opening 22, and are parallel to the fan center axis P.
3 has a vertical portion x facing the outside of the inlet opening 23, and the tangent inclination angle gradually changes toward the outlet opening 22 side from the vertical portion x so that the vertical portion x gradually changes in the middle of the internal air passage 21 (that is, the inlet opening 23). The tangential inclination direction to the fan center axis P is reversed at an intermediate portion between the fan opening axis 22 and the outlet opening 22). The angle gradually becomes smaller, and is finally formed on a convex curved surface that is continuous with the inner surface of the outer air passage of the linear air passage portion 21a.

The surface S of the inner body 20A on the side of the internal air passage 21 is
y (i.e., the inner surface of the concave air passage of the internal air passage 21) has a horizontal portion y at a position orthogonal to the fan center axis P at the introduction opening 23 and from there toward the outlet opening 22. The tangential inclination angle with respect to the fan center axis P gradually becomes smaller, and is finally formed into a concave curved surface that is continuous with the inner air path inner surface of the linear air path portion 21a.

More specifically, the inner surface S
Of x, an area between the inner surface of the outer air passage of the linear air passage portion 21a and the reversal point u is an arc surface having a radius Ra connected in a tangential direction to the inner surface of the outer air passage of the linear air passage portion 21a, The portion between the reversal point u and the above-described vertical portion x of the convex-side air passage inner surface Sx is an arc surface having a radius Rb and a radius Rb continuous in a tangential direction with respect to each of the vertical portion x. Between the inner air passage inner surface of the linear air passage portion 21a and the horizontal portion y of the concave air passage inner surface Sy, the inner air passage inner surface of the linear air passage portion 21a and the horizontal portion y respectively. It is an arc surface with a radius Rc that continues in the tangential direction.

That is, the inner surface S of the convex air passage on the inner air passage 21
By forming each of x and the concave-side air passage inner surface Sy in the above-described shape, the body size G in a direction orthogonal to the fan center axis P and the fan center axis P direction In order to obtain a high heat exchange efficiency by uniformizing the air flow passage speed in the cooler (or heater) 5 while minimizing the body size H as much as possible. Therefore, it is possible to effectively reduce the noise generated.

Each of the above-mentioned radius Ra and radius Rc is selected from the following formula with respect to the opening width W of the outlet opening 22. Ra = K2 · W Rc = K3 · W An appropriate value is selected for each of the coefficients K2 and K3. Has been decided.

The coefficients K1, K2, and K3, the radius Rb, the length Ha of the straight air passage portion 21a, the length L of the horizontal portion y, and the bottom peripheral surface of the conical inner body 20A. Are determined by the value of the pressure loss generated when the airflow As passes through the internal air passage 21, the noise reduction characteristics, and the like.

As one of the selection criteria for each of the above values,
The surface wind speed Vi at the introduction opening 23 is reduced by the linear air passage portion 21.
It may be adopted that the wind speed Vo at a is about 2/5 to 1/2.

In the figure, the magnitude relationship between the radius Ra and the radius Rb is Ra <Rb. However, depending on the conditions, there may be a case where Ra ≧ Rb, and in the figure, the center Oa of the arc surface of the radius Ra is shown.
And the center Oc of the arc surface having the radius Rc are arranged at the same height below the upper wall of the box body 2 by the dimension Ha, but depending on conditions, the fan on the inner surface of the outer air passage in the straight air passage portion 21a may be used. The center Oc is set to the center Oa in a state where the length of the inner air passage inner surface in the center axis direction of the fan is made larger than the length in the center axis direction.
In some cases, the center Oc may be positioned lower than the center Oa.

Another Embodiment Next, another embodiment will be described.

The fan suction-side airflow guide silencer according to the present invention is not limited to the case of suction by an axial fan, but can also be applied to the case of suction by a centrifugal fan as shown in FIG. In FIG. 4, the axis P indicates the center axis of the suction port 8 of the centrifugal fan 7 (corresponding to the rotor axis of the centrifugal fan 7).

In the above-described embodiment, as an example of application to an air conditioner, air As passed through a cooler or a heater is introduced from the introduction opening 23. For example, as an example of application to a ventilation device, a parking lot is applied. For example, in the ventilation target area such as a configuration in which air in the area is introduced from the introduction opening 23 through the gallery, the fan suction-side airflow guide silencer according to the present invention can use various gases in various fields as the introduction target gas. it can.

In the above embodiment, the box 2 is rectangular in plan view, and the cooler 5 and the like are provided on the two short side surfaces. However, the plane shape of the box 2 is square, circular, or any other shape. When the cooler 5 or the like is provided, the number of the mounted surfaces may be three or more, or the cooler 5 or the like may be provided in an arc shape.

The sound absorbing material 24 constituting the air path wall of the internal air path 21 is not limited to glass wool, and various materials can be used.

As going from the inlet opening 23 to the outlet opening 22, the direction of the air path gradually changes from a direction orthogonal or oblique to the center axis P of the outlet opening 22 to a direction parallel to the center axis P of the outlet opening 22. In forming the internal air passage 21 having a shape in which the air passage width is gradually reduced, the detailed shape of the convex air passage inner surface Sx and the concave air passage inner surface Sy of the internal air passage 21 is as follows. Various configuration changes are possible within the scope described in the claims.

The shape of the outlet opening 22 and the shape of the internal air passage 21 as viewed from the center axis P of the outlet opening 22 are not limited to circular shapes, but may be polygonal as shown in FIG. May be formed.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment.

FIG. 2 is a cross-sectional plan view showing an embodiment.

FIG. 3 is an enlarged vertical sectional view of a main part showing the embodiment.

FIG. 4 is a longitudinal sectional view showing another embodiment.

FIG. 5 is a sectional plan view showing another embodiment.

FIG. 6 is a longitudinal sectional view showing a conventional example.

[Explanation of symbols]

 7 Fan 8 Inlet 20 Body 20A Inner body 20B Outer body 21 Inner airway 21a Straight airway part 22 Outlet opening 23 Inlet opening 24 Sound absorbing material As Airflow P axis core Sx Inner airway side of outer body Sy Inner body Inside wind path side u Inversion point

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 64-13299 (JP, U) JP-B 63-44960 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 29/40-29/56 F04D 29/66

Claims (2)

(57) [Claims] 1. A conical inner cylinder (20A) and an annular outer cylinder (2).
0B) at the inner center of the outer shell (20B).
Place the top of the torso (20A) in a position
The sound absorbing material (24) is placed between (20A) and (20B) and the
An annular internal air passage (21) made of a material is formed, and the inner body (2 ) is formed as an opening on one end side of the internal air passage (21).
0A) formed at the top side between both bodies (20A) and (20B)
The annular opening is concentric with the fan inlet (8)
And an outlet (22) communicating with the inner air passage (21).
Direction orthogonal or oblique to the center axis (P) of (22)
At the bottom side of the inner body (20A) between the two bodies.
Air flow (As) is introduced from the periphery of the vessel through the annular opening
And a surface (S) of the outer body (20B) on the side of the internal air passage (21).
x) with the inlet opening (23) and the outlet opening (22)
Tangent to the central axis (P) at an intermediate portion between
Having a reversal point (u) in the direction, and the center axis center (P)
(Ha + Ra) in the direction along the axis and the center axis center
The dimension ((GD) / 2) in the direction perpendicular to (P) is
The inner and outer radii of the annular shape of the outlet opening (22)
With a convex curved surface having a cross-sectional shape that is not less than the difference (W)
The surface of the inner air passage (21) side in said barrel (20A) (S
y) from the inlet opening (23) to the outlet opening (2).
Increasing tangent to the center axis (P) toward 2)
The internal air passage (21) is located in front of the introduction opening (23) with a concave curved surface having a small angle.
The direction of the air path is closer to the center as the head moves toward the outlet (22).
Gradually changes to a direction parallel to the axis (P),
First, a fan suction-side airflow guide silencer having an air passage whose air passage width is gradually reduced . 2. The derivation in the internal air passage (21).
At the end on the opening (22) side, an annular shape of the outlet opening (22) is provided.
With an air path width equal to the inner and outer radius difference (W) in the shape ,
Straight air path portion (21a) extending parallel to the mandrel (P)
Fan suction side airflow guiding muffler of claim 1 is formed with.